Eye bank versus surgeon prepared DMEK tissues: influence on adhesion and re-bubbling rate

Abstract

AimTo investigate the difference in adhesion and rebubbling rate between eye bank and surgeon prepared Descemet membrane endothelial keratoplasty (DMEK) tissues.MethodsLaboratory and clinical retrospective comparative interventional case series. Research corneal tissues were obtained for laboratory investigation. The clinical study involved patients with endothelial dysfunction who underwent DMEK surgery and tamponade with air. Tissues were stripped using a standard DMEK stripping technique (SCUBA) and shipped as prestripped or loaded in a 2.2 intra-ocular lens cartridge with endothelium facing inwards (preloaded) before transporting from the eye bank to the surgeon. For surgeon prepared tissues, all the grafts were stripped in the theatre and transplanted or stripped in the laboratory and tested immediately. Adhesion force and elastic modulus were measured in the centre and mid-periphery in a laboratory ex vivo investigation using atomic force microscopy, while rebubbling rates were recorded in the clinical study.ResultsThere was no difference in endothelial cell viability between surgeon or eye bank prepared tissue. Surgeon-stripped DMEK grafts in the laboratory investigation showed significantly higher elastic modulus and adhesion force compared to prestripped and preloaded tissues (p<0.0001). In the clinical data, rebubbling rates of 48%, 40% and 15% were observed in preloaded, prestripped and surgeon-stripped DMEK grafts, respectively. Rebubbling rates were significantly associated with combined cataract surgery (p=0.009) and with time from harvesting the graft to the surgery (p=0.02).ConclusionsDecreased adhesion forces and elastic modulus in eye bank prepared tissues may contribute to increased rebubbling rates.

Rebubbling rate in preloaded versus surgeon prepared DSAEK

“…In the pre-loaded DSAEK group, the lenticular stroma is exposed to the transport medium to a greater extent than surgeon cut and this may lead to deposition of the dextran, which may interact with the interfacial matrix on the surface. This may potentially interfere with attachment as has been postulated by Romano et al 13 However, as we did not demonstrate significance, we are unable to conclude this finding. In the literature we found that the effect of transport and processing time, and stromal exposure to dextran on graft characteristics to be negligible.…”

“Endothelium-Out” and “Endothelium-In” Descemet Membrane Endothelial Keratoplasty (DMEK) Graft Insertion Techniques: A Systematic Review With Meta-Analysis

“…The concept of “endothelium-in” DMEK insertion techniques have been recently introduced ( 33 – 37 , 44 , 45 ). The grafts are folded, usually in a trifold, with the endothelium on the inside.…”

“…These factors in “endothelium-in” techniques reduce the technical difficulties of intracameral graft orientation and unscrolling, making DMEK procedures more controlled and predictable. Some of these “endothelium-in” techniques also use devices created to mimic DSAEK techniques, which many corneal surgeons are accustomed to ( 33 , 44 , 45 ). Various laboratory studies have reported no significant differences in endothelial cell loss when DMEK grafts were loaded “endothelium-in” and pulled-through or loaded “endothelium-out” and injected-through different graft insertion devices ( 62 – 64 ).…”

Effect of Descemet Membrane Endothelial Keratoplasty Graft Storage Time on Graft Elasticity

“…Other studies explored different factors that affect DMEK graft elasticity: Romano et al 19 reported decreased adhesion forces in prestripped and preloaded DMEK tissue in dextran-based media in comparison with surgeon-stripped DMEK grafts. Moreover, the DMEK graft detachment rate after the surgery was significantly higher in a prestripped and preloaded DMEK tissue group.…”